What risk does progestin use may increase if a female adult patient is taking a progestin-only oral contraceptive, or minipill?

Tubal or ectopic pregnancy

Women taking the minipill have a higher incidence of tubal and ectopic pregnancies, possibly because progestin slows ovum transport through the fallopian tubes. Endometriosis, female hypogonadism, and premenstrual syndrome are not associated with progestin-only oral contraceptives.